The U.K.'s intelligence agency Government Communications Headquarters (GCHQ) has reportedly built an automated system to track the hotel bookings of foreign diplomats when travelling abroad for international summits or work meetings.

The tracking is done through a secret program called "Royal Concierge" that automatically monitors booking confirmation messages sent by 350 upscale hotels from around the world to email addresses hosted on government domains (gov.cctld), German magazine Der Spiegel reported Monday based on documents leaked by former U.S. National Security Agency contractor Edward Snowden.

The program, which was launched in 2010 and is described internally as an "innovation," alerts GCHQ analysts in advance of what cities and hotels foreign diplomats intend to visit, Der Spiegel said.

Another document reportedly seen by the German publication explains that this information can be used to target those diplomats for intelligence gathering using a variety of techniques like wiretapping the telephones and fax machines in their hotel rooms, monitoring their computers when connected to the hotel network or with more specialized attacks executed by "Active Approach Teams" that are "designed to bridge the gaps to communications that our conventional accesses cannot reach."

One GCHQ presentation describing "Royal Concierge" was titled "Tales from the Wild, Wild West of GCHQ Operational Datamining" and some slides suggested that a possible extension to the program would be to target "car hires" used by diplomats, Der Spiegel said.

The report follows a public hearing in the U.K. Parliament last week in which the heads of the three British intelligence agencies, the MI5, MI6 and GCHQ, were questioned about the activities of the British intelligence community in light of media reports of mass data collection programs revealed by Edward Snowden.

According to a BBC report, GCHQ's chief Sir Iain Lobban said during that hearing that the agency acts within the law and its employees are focused on combating terrorism and criminals, not spying on innocent people.

However, the type of intelligence gathered from foreign diplomats might be of interest to the U.K.'s Secret Intelligence Service (SIS or MI6), whose chief, Sir John Sawers, said during the same hearing that his agency acquires secrets "other countries don't want us to know."

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